vfs: spread struct mount - __lookup_mnt() result

switch __lookup_mnt() to returning struct mount *; callers adjusted.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/internal.h

@@ -15,6 +15,7 @@ struct super_block;
 struct file_system_type;
 struct linux_binprm;
 struct path;
+struct mount;
 
 /*
  * block_dev.c
@@ -46,7 +47,6 @@ extern void __init chrdev_init(void);
 extern int copy_mount_options(const void __user *, unsigned long *);
 extern int copy_mount_string(const void __user *, char **);
 
-extern struct vfsmount *__lookup_mnt(struct vfsmount *, struct dentry *, int);
 extern struct vfsmount *lookup_mnt(struct path *);
 extern int finish_automount(struct vfsmount *, struct path *);
 

fs/mount.h

@@ -13,3 +13,5 @@ static inline int mnt_has_parent(struct vfsmount *mnt)
 {
 	return mnt != mnt->mnt_parent;
 }
+
+extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *, int);

fs/namei.c

@@ -36,6 +36,7 @@
 #include <asm/uaccess.h>
 
 #include "internal.h"
+#include "mount.h"
 
 /* [Feb-1997 T. Schoebel-Theuer]
  * Fundamental changes in the pathname lookup mechanisms (namei)
@@ -884,7 +885,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
 			       struct inode **inode)
 {
 	for (;;) {
-		struct vfsmount *mounted;
+		struct mount *mounted;
 		/*
 		 * Don't forget we might have a non-mountpoint managed dentry
 		 * that wants to block transit.
@@ -898,8 +899,8 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
 		mounted = __lookup_mnt(path->mnt, path->dentry, 1);
 		if (!mounted)
 			break;
-		path->mnt = mounted;
-		path->dentry = mounted->mnt_root;
+		path->mnt = &mounted->mnt;
+		path->dentry = mounted->mnt.mnt_root;
 		nd->flags |= LOOKUP_JUMPED;
 		nd->seq = read_seqcount_begin(&path->dentry->d_seq);
 		/*
@@ -915,12 +916,12 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
 static void follow_mount_rcu(struct nameidata *nd)
 {
 	while (d_mountpoint(nd->path.dentry)) {
-		struct vfsmount *mounted;
+		struct mount *mounted;
 		mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1);
 		if (!mounted)
 			break;
-		nd->path.mnt = mounted;
-		nd->path.dentry = mounted->mnt_root;
+		nd->path.mnt = &mounted->mnt;
+		nd->path.dentry = mounted->mnt.mnt_root;
 		nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
 	}
 }

fs/namespace.c

@@ -464,20 +464,20 @@ static void free_vfsmnt(struct vfsmount *mnt)
  * @dir. If @dir is set return the first mount else return the last mount.
  * vfsmount_lock must be held for read or write.
  */
-struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
+struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
 			      int dir)
 {
 	struct list_head *head = mount_hashtable + hash(mnt, dentry);
 	struct list_head *tmp = head;
-	struct vfsmount *p, *found = NULL;
+	struct mount *p, *found = NULL;
 
 	for (;;) {
 		tmp = dir ? tmp->next : tmp->prev;
 		p = NULL;
 		if (tmp == head)
 			break;
-		p = list_entry(tmp, struct vfsmount, mnt_hash);
-		if (p->mnt_parent == mnt && p->mnt_mountpoint == dentry) {
+		p = list_entry(tmp, struct mount, mnt.mnt_hash);
+		if (p->mnt.mnt_parent == mnt && p->mnt.mnt_mountpoint == dentry) {
 			found = p;
 			break;
 		}
@@ -491,13 +491,18 @@ struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
  */
 struct vfsmount *lookup_mnt(struct path *path)
 {
-	struct vfsmount *child_mnt;
+	struct mount *child_mnt;
 
 	br_read_lock(vfsmount_lock);
-	if ((child_mnt = __lookup_mnt(path->mnt, path->dentry, 1)))
-		mntget(child_mnt);
-	br_read_unlock(vfsmount_lock);
-	return child_mnt;
+	child_mnt = __lookup_mnt(path->mnt, path->dentry, 1);
+	if (child_mnt) {
+		mnt_add_count(child_mnt, 1);
+		br_read_unlock(vfsmount_lock);
+		return &child_mnt->mnt;
+	} else {
+		br_read_unlock(vfsmount_lock);
+		return NULL;
+	}
 }
 
 static inline int check_mnt(struct vfsmount *mnt)

fs/pnode.c

@@ -289,7 +289,8 @@ static inline int do_refcount_check(struct vfsmount *mnt, int count)
  */
 int propagate_mount_busy(struct vfsmount *mnt, int refcnt)
 {
-	struct vfsmount *m, *child;
+	struct vfsmount *m;
+	struct mount *child;
 	struct vfsmount *parent = mnt->mnt_parent;
 	int ret = 0;
 
@@ -307,8 +308,8 @@ int propagate_mount_busy(struct vfsmount *mnt, int refcnt)
 	for (m = propagation_next(parent, parent); m;
 	     		m = propagation_next(m, parent)) {
 		child = __lookup_mnt(m, mnt->mnt_mountpoint, 0);
-		if (child && list_empty(&child->mnt_mounts) &&
-		    (ret = do_refcount_check(child, 1)))
+		if (child && list_empty(&child->mnt.mnt_mounts) &&
+		    (ret = do_refcount_check(&child->mnt, 1)))
 			break;
 	}
 	return ret;
@@ -328,14 +329,14 @@ static void __propagate_umount(struct vfsmount *mnt)
 	for (m = propagation_next(parent, parent); m;
 			m = propagation_next(m, parent)) {
 
-		struct vfsmount *child = __lookup_mnt(m,
+		struct mount *child = __lookup_mnt(m,
 					mnt->mnt_mountpoint, 0);
 		/*
 		 * umount the child only if the child has no
 		 * other children
 		 */
-		if (child && list_empty(&child->mnt_mounts))
-			list_move_tail(&child->mnt_hash, &mnt->mnt_hash);
+		if (child && list_empty(&child->mnt.mnt_mounts))
+			list_move_tail(&child->mnt.mnt_hash, &mnt->mnt_hash);
 	}
 }